Nonvolatile semiconductor memory device

An electrically erasable and rewritable semiconductor memory device including at least one memory block, comprising:

• a WP signal generator for generating a WP signal for controlling protection of data stored in the memory block;
• a protect state setting section for setting a protect state for the memory block, the data stored in the memory block being protectable from erase/write operations when the protect state is set to the memory block;
• and
• a data protecting section for prohibiting the erase/write operations for the memory block to which the protect state is set, in the case where the WP signal is active;
• wherein the WP signal generator includes:
• a WP release command identifying section for receiving a WP release command represented by at least one predetermined value selected from values of data and values of at least one address which are input in at least one bus cycle, and for identifying the WP release command by detecting the at least one predetermined value;
• and
• a generating section for inactivating the WP signal when the WP release command is identified during the WP signal is active.

A method for protecting data stored in an electrically erasable and rewritable semiconductor memory device including at least one memory block, the method includes the steps of:

• generating a WP signal for controlling protection of the data stored in the memory block;
• setting a protect state for the memory block, the data stored in the memory block being protectable from erase/write operations when the protect state is set to the memory block;
• prohibiting the erase/write operations for the memory block to which the protect state is set in the case where the WP signal is active;
• and
• identifying a WP set command,
• wherein the WP set command identifying step includes the steps of:
• inputting a WP set command represented by at least one predetermined value selected from values of data and values of at least one address using at least one bus cycle;
• identifying the WP set command by detecting the at least one predetermined value;
• and
• activating the WP signal when the WP set command is identified during the WP signal is inactive.

A method for protecting data stored in an electrically erasable and rewritable semiconductor memory device including at least one memory block, the method including the steps of:

• generating a WP signal for controlling protection of the data stored in the memory block;
• setting a protect state for the memory block, the data stored in the memory block being protectable from erase/write operations when the protect state is set to the memory block;
• prohibiting the erase/write operations for the memory block to which the protect state is set in the case where the WP signal is active;
• and
• identifying a WP release command,
• wherein the WP release command identifying step includes the steps of:
• inputting a WP release command represented by at least one predetermined value selected from values of data and values of at least one address using at least one bus cycle;
• identifying the WP release command by detecting the at least one predetermined value;
• and inactivating the WP signal when the WP set command is identified during the WP signal is active.